Process for lapping cylinders



Nov. 2 1926. I 1,605,160

v 1 4 B. H. BLOQD H PROCESS FOR LAPPING, CYLINDERS Original Filed Sept. 26. 1921 Patented Nov. 2, 1926.

UNITED sTArEs PATENT OFFICE.

BRYANT H. BLOOD, OF HARTFORD, CONNECTICUT, ASSIGNOR TO PRATT & WHITNEY COMPANY, OF NEW YORK, N.'Y., A CORPORATION OF NEW JERSEY.

PROCESS FOR LAPPING CYLINDERS.

Application filed September 26, 1921, Serial 110. 508,188. Renewed September 14, 1926.

This invention relates to an improved method and apparatus for lapping cylindrical surfaces. Particularly, the invention relates to process or method of simultaneously lapping the cylindrical surfaces of a plurality of gages.

An object of the present invention is to provide means to mount the articles being lapped in a holding member, or spider, disposed in a symmetrical grou and in a manner that they may be rotate about their individual aXes without parts of the holding member coming into contact with their cylindrical or end faces.

Another object of the invention is to provide means to rotatably mount the cylinders being lapped in the holding member so that their axes are non-radial of the holding member but disposed so that they are tangent to a circle concentric with the holding member. I

Another object of the invention is to provide a number of short arbors upon which the cylinders to be lapped may be individually mounted so that they may rotate free- 1y thereupon, each arbor being held non-rotatably in the holding'member but free to adjust itselftoward'or from one of the laps and adapted to be placed with either end pointing outward of the holding member.

Another object of the invention is to lap a group or series of cylinders simultaneously in accordance with a method involving simultaneous lapping movements of the cylinders and continuous rotary movement thereof, the lapping movements being caused by rotation of one of the laps.

A further object of the invention comprises permitting rotation of the holding member between the two opposed laps about its own center and also bodily in acircle concentric with the rotating lap. Preferably, both movements of the holding member are induced by the rotary movement of one of the laps and by means constraining the holding member to a definite path.

Also the invention comprises the method of lapping the cylinders for a period of time, removing the upper lap, transposing or interchanging the positions of some of the cylinders in accordance with a predetermined definite planand repeating the lapping and interchanging until the cylinders are of identical predetermined diameters from end to end.

With these and other objects in view, my invention consists in the features of construction and operation set forth in the following specification and illustrated in the accompanying drawing.

In the accompanying drawing annexed hereto and forming a part of, this specification, I have shown my invention embodied in and adapted to be carried out in a gage lapping machine but it will be understood that the invention can be otherwise em-- bodied and that the drawing is not to be construed as defining or limiting the scope of the mvention, the claims appended to this specification being relied upon for that purpose.

In the drawing:

Figure l is a sectional view in elevation of the parts forming the present invention, the section being taken on line 1 1 of Fig. 2.

Fig. 2 is a plan view of the apparatus with the upper or rotatable lap removed.

Fig. is a detail sectional view of one of the articles being lapped mounted on its individual arbor.

Fig. 4 is an end view of the same.

' In the above mentioned drawing, 1 have shown but one embodiment of a 'machine adapted to carry out my invention which is now deemed preferable but it is to be understood that changes and modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

Briefly, the machine adapted to carry out my invention, in its broadest aspect comprises the following principal parts; first, a lower or stationary lap, the upper surface of which is carefully surfaced to a perfect plane and charged with a suitable abradant material; second, a rotatable lap mounted above the stationary lap and adapted to adi'ust itself as to parallelism relative to the ower lap, the lower surface of this upper lap being also ,carefully surfaced and" char ed with suitable abradant material; thir a holding member disposed between the laps wherein a plurality of articles to be lapped may be mounted and retained in a regular or systematic series; fourth, a crank rotatably mounted in the lower or stationary lap and also in the holding member con-' straining the holding member to rotate about its center and to move bodily in a too circle about the center of the lower or stationary lap; and fifth, arbors disposed ymmetrically about the holding member upon which the articles may be rotatably mounted.

The method of carrying out the present invention comprises the following principal steps; mounting the cylinders to be lapped in the holding member individually on the arbors above referred to, and rotating one of the laps, preferably the upper one, while the holding member and cylinders are disposed therebetweeh, continuing the lapping operation for a predetermined time, then removing the upper lap. and transposing or rearranging tie relative positions of the cylinders in the group, and repeating the lapping and transposing operations alternately until identical diameters are obtained. Referring more in detail to the figures of the drawing, at is shown a suitable base upon which may be fastened by any suitable means a lap 11. The upper surface 12 of this lap is surfaced to a perfect plane and is charged with a suitable abradant material. The lap 11 is provided with a central hole 13 for a purpose presently to be described. Above the stationary or lower lap 11 is a lap 15 which may be rotated by means of a shaft 16. The connection between the shaft 16 and the lap 15, as indicated by the screws 17 and the holes 18 through the plate 19 to which the shaft 16 is fastened, is such that the la 15 may adjust itself as to parallelism with t e surface 12 of the lap 11. The lower surface 20 of the rotatable lap 15 is also carefully surfaced so that it is perfectly plane and is charged with a suitable abradant material.

Disposed between the contiguous surface 12 and 20 of the two laps '11 and 15 is a holding member, or spider 25, most clearly shown in Fi 2. This is preferably circular and provide with a small hole 26 in its center in which a bearing member 27 may be disposed. Arranged about the periphery of the holding member or spider are a plurality of articles A preferably symmetrically disposed about the -center 26. These, as shown, are preferably disposed in elongated arcuate openings 31, four of these openings being shown, each of which has four arbors 30 mounted therein upon which the articles are mounted. Preferably, the arbors 30 may be supported in position in slots 32 and 33 cut through the spider 25, one end of the arbors 30 being cut away on either side as shown at 34 in Fig. 3 so that they will be non-rotatably held relative to the spider. Preferably, I make these arbors 30 of a steel rod of. a diameter as shown at 35, one end, as referred to above, being cut away to leave the end 34 with flat sides. The opposite end of the arbor 30 is screw threaded as shown at 36 upon which a nut 37 may be threaded and locked in position by small screws 38. The extreme outer end 39 of the arbor may be circular and adapted to fit freely within one of the depressions 32. Between the head and the adjustable nut 37 on the arbors 30 I may mount washers or spacing members 4-0, any thickness being used so that they will accommodate the particular length of gage being lapped. Preferably, the slots 32 and 33 are of the same width, and the parts 34 and 39 of the arbors 30 are of the same thickness so that the arbors 30 may be disposed in the spider with either end of the arbors 30 extending outward. Also the slots 32 and 33 are large enough to permit sliding movement of the arbors.

From this construction, it will be seen that any diameter of cylinders A may be mounted on the arbors 30 and rotatably held thereon by the spacing members 40 and the nut 37. Further, when mounted on the arbors 30, the articles A being lapped are held in a symmetrical series evenly spaced about the holding member or spider 25. The arbors 30 within the slots 32 and 33 are free to ad just themselves vertically toward or from either of the laps so that slight variations in diameters of the articles may be compensated for by slight vertical movement of the arbors.

In operation, the articles to be lapped are rotatably mounted individually upon their respective arbors, and the arbors disposed in position in the spider 25 while resting on lap 11. One end of a crank projects through the bearing member 27 the opposite end of the crank 50 being disposed as shown in Fig. 1 in the hole 13 provided in the center of the stationary lap 11. Withthe parts so adjusted, the lap 15 is mounted so that it will rest upon the upper surfaces of the articles to be lapped. The shaft is then rotated by any suita le means, the lap 15 being free to adjust itself as to parallelism relative to the lapping surface 12 of the stationary lap 11 and at all times contacts with the upper surfaces of the larger articles being lapped. Rotation of the upper lap 15 by the shaft '16 tends to rotate the holding member or spider 25 in the same direction and the action of the short crank 50 or other suitable means in combination with the rotative action of the upper lap forces the holding member 25 not only to rotate about its own center 26 but also to rotate bodily about the center 13. The holding member 25 is therefore bodily moved about the center of rotation of the laps 11 and 15 and is also given a free rotative movement about its own axis or center. As the articles are disposed non-radially, the effect of this rotative and planetary movement of the holding member causes a lap ing movement of t e articles A across t e lapping surfaces 12 and 20 while the articles A are constantly rotating.

After the articles have been lapped a predetermined length of time while retained in one position in the holding member, the upper lap is removed and the articles A in the holding member are transposed or interchanged relative to each other, the upper lap 15 is then replaced and another lapping operation takes place. These alternate lapping and interchanging operations may take place repeatedly until identical diameters are obtained on the cylinders and the diameters are accurately lapped to a precise predetermined size.

' In carrying out the interchanging or transposing operation, advantage may be taken of the plan disclosed in the Patent No. 1,486,341 to W. E. Hoke granted March 11, 1924, to which reference may be had for a full description. The essential feature of this is that variations in diameters of the articles are so distributed that the upticles.

One method of transposing is diagrammatically-shown in Fig. 2 in which the double arrows point to the articles which are moved and indicate also the positions to which they are transposed. Simultaneously with the transposing of alternate cylinders to diametrically opposite positions, the cylinders may be turned end for end to further distribute variations in diameters of the cylinders and to aid in obtaining absolute'precision.

What I claim is:

1. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical, grou in a holding member disposed between a pair of opposite-,

1y disposed laps having plane lapping surfaces, and causin lapping movements between said cylin rical surfaces and laps while said articles are being continuously'rotated, and while said holding member is held eccentric to said laps.

2. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group upon individual arbors so that they may rotate thereon in a holding member disposed between a pair of oppositely disposed laps, and cans ing lapping movements between said cylindrical surfaces and laps while said articles are being continuously rotated, and while paid holding member is held eccentric to said aps.

3. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group in a holding member disposed between a pair of oppositely disposed laps, and causing lapping movements between said cylindrical surfaces and laps while said articles are being continuously rotated in one direction, and while said holding member is held eccentric to said laps.

per lap contacts only with the larger ar-'.

1. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group in a holding member disposed between a pair of oppositely disposed laps, and rotating one of said laps thereby causing lapping movements between said cylindrical surfaces and laps while said articles are being continuously r0- tated, and while said holding member is held eccentric to said laps.

5. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group in aholding member disposed between a pair of opposite-- ly disposed laps, permitting one of the laps to adjust itself relative to parallelism with the other lap, and causing lapping movements between said cylindrical surfaces and laps while said articles are being continuously rotated, and while said holding member is held eccentric to said laps.

('5. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group in a holding member disposed between a pair of oppositely disposed laps having plane lapping surfaces, permitting one of the laps to adjust itself relative to parallelism with the other lap and causing lapping movements between said cylindrical surfaces and the plane surfaces of the laps while said articles are bein continuously rotated, and while said holding member is held eccentric to said laps.-

7. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group in a holding member disposed between a pair of oppositely disposed laps, permitting one of the la s to adjust itself relative to parallelism Wltlt the other lap, and rotating one of said laps thereby causing lapping movements between said cylindrical surfaces and laps while said articles are being continuously rotated, and while said holding member is held eccentric to said laps.

8. A process of lapping cylindrical sur faces of articles comprising, arranging said articles in a symmetrical group in a holding member disposed between a pair of oppositely disposed laps, causing lapping movements between said cylindrical surfaces and laps for a predetermined time while said articles are bein continuously rotated and while said holding member is held eccentric to said laps, transposing the position of some of sa d articles in accordance with a predetermined method, and repeating said lapping operation.

9. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group in a holding member disposed between a pair of oppositely dis osed laps, permitting one of the laps to a just itself relative to parallelism with the other lap, causing lapping movements between said cylindrical surfaces and laps for a predetermined time while said articles are being continuously rotated and while said holding member is held eccentric to said laps, transposing the position of some of said articles in accordance with a predetermined method, and repeating said lapping operation.

10. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group in a holding member disposed between a pair of oppositely disposed laps having plane lapping surfaces, permitting one of the laps to adjust itself relative to parallelism with the other lap, causing lapping movements between said cylindrical surfaces and the plane surfaces of the laps while said articles are being continuously rotated and while said holding member is held eccentric to said laps, transposing the position of some of said articles in accordance with a predetermined method, and repeating said lapping operation.

. 11. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group in a holding member disposed between a pair of oppo sitely disposed laps, causing lapping movements between said cylindrical surfaces and lap for a predetermined time while said articles are being continuously rotated and while said holding member is held eccentric to said laps, transposing the position of some of said articles in accordance with a predetermined method, and repeating said lapping and transposing operations alternately until identical diameters are obtained on all of said articles.

12. A process of lapping cylindrical surfaces of articles comprising, arranging said articles in a symmetrical group in a holding member disposed between a pair of oppositely disposed laps having plane lapping surfaces, permitting one of the laps to adjust itself relative to parallelism with the other lap, causing lapping movements between said cylindrical surfaces and laps while said articles are continuously rotated and while said holding member is held eccentric to said laps, transposing the position of some of said articles in accordance with a predetermined method, and repeating said lapping and transposing operations alternately until identical and predetermined diameters are obtained on all of said articles.

In testimony whereof, I hereto affix my signature.

BRYANT H. BLOOD. 

